How to fix date format in Tasks app

Hello imsimj,

Welcome to Microsoft Q&A.

I understand that your Tasks app is displaying incorrect dates (future dates overridden and shown as past/overdue), and completed tasks are reappearing.

This usually happens because of regional date format mismatch or sync inconsistencies between Outlook, Microsoft To Do, and the underlying Microsoft 365 account. Cached or corrupted task metadata may also cause the app to revert dates.

To solve the problem, you can try some options below:

Option 1: Verify date & time settings:

1. Open Windows Settings > Time & Language.
2. Ensure your Time zone and Region format (short date/long date) match your preferred format (e.g., dd/MM/yyyy vs MM/dd/yyyy).
3. If using mobile, check your phone’s region and language settings.
4. Restart the Tasks/To Do app and recheck the task date.

Option 2: Reset Taks sync:

1. In Microsoft To Do, go to Settings > Reset app (Windows) or Sign out & Sign in (mobile).
2. This forces a full re-sync with your Microsoft 365 account.
3. After signing back in, re-enter the task and confirm if the correct date is preserved.

Option 3: Clean cached date in Outlook if Tasks is linked with Outlook:

1. Open Outlook Desktop > File > Account Settings > Data Files > select your account > Settings.
2. Run Repair.
3. Restart Outlook and allow it to resync Tasks.

Option 4: Use web version to validate:

1. Go to outlook.office.com/tasks.
2. Create a new task with a September 2026 start date.
3. If it shows correctly on the web, but not in the app, the issue is with the local app cache. In this case, reinstall the Tasks/To Do app.

Please let me know if you need further assistance.

Best regards,

Alex | Microsoft Q&A Specialist

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Are you referring to tasks in Outlook, or the To Do app? Or maybe you are referring to Tasks in Microsoft Teams (these may be more or less integrated)? Please clarify. Since you mention an older thread, a link to that one might also be helpful for anyone trying to diagnose the issue you have encountered.